Conventionally, electric dust collection devices and deodorization devices adopt a technique of providing a corona discharge unit for bringing dust into a charged state by corona discharge and capturing the charged dust by a dust collector. In general, this corona discharge unit is configured to apply high voltage to discharge electrodes formed by wire electrodes having a wire diameter of about 0.1 mm to 1.0 mm so as to generate corona discharge between the discharge electrodes and counter electrodes. The thinner the used wire electrodes are, the lower the applied voltage for generating discharge can be. However, when the thin wires are used, local discharge and disconnection may be caused by, for example, corrosion or sputtering. To effectively collect dust, charge needs to be applied to almost all amount of air containing the dust. For this reason, it is preferable to increase the surface area of the discharge electrodes.
In the context of such matters, there has been proposed a discharge electrode that is formed by radially etching or press-cutting a quadrangular thin stainless steel plate having a thickness of 0.1 mm to 0.2 mm (see, for example, Patent Literature 1).
There have also been proposed plate-shaped (ribbon-shaped) discharge electrodes that are made of metal, such as tungsten, and that are disposed between counter electrodes with spaces therebetween (see, for example, Patent Literature 2).